THE NERVOUS SYSTEM OF THE OX 841 



important special features correlated chiefly with the arrangement of the 

 digits. 



The radial nerve is continued below the elbow by a large cutaneous branch 

 (N. cutaneus antibrachii dorsalis) which emerges at the lower border of the lateral 

 head of the triceps and descends on the dorsal aspect of the limb. It commu- 

 nicates above the carpus with the lateral cutaneous branch of the median nerve and 

 terminates in three dorsal digital nerves; two of these descend along the axial 

 or interdigital side of the dorsal surface of the chief digits, and the third along the 

 medial (abaxial) side of the medial chief digit. 



The ulnar nerve divides at a variable distance down the forearm into two 

 branches. The dorsal (or superficial) branch emerges between the tendons of the 

 ulnaris lateralis and flexor carpi ulnaris, and is continued as the lateral dorsal 

 digital nerve on the lateral chief digit. The volar (or deep) branch descends along 

 the superficial digital flexor, gives a branch to the suspensory ligament below the 

 carpus, and unites with the lateral branch of the median nerve to form the lateral 

 volar digital nerve (N. digitalis lateralis digiti IV). 



The median nerve is much larger than the ulnar. It passes beneath the prona- 

 tor teres, descends the forearm as in the horse, and divides in the distal part of the 

 metacarpus into two branches. The medial branch gives twigs to the medial small 

 digit and is continued on the medial side of the volar surface of the medial chief digit 

 as the medial volar digital nerve (N. digitalis medialis digiti III) ; it also concurs 

 with the lateral branch in forming the two digital nerves which descend along the 

 interdigital aspect of the chief digits. The lateral branch is larger. It bifurcates, 

 and one division unites with the twig from the medial branch to form a common 

 digital trunk. From the latter two digital nerves proceed as mentioned above; 

 these are the lateral and medial volar digital nerves of the medial and lateral 

 chief digits respectively (N. digitalis volaris lateralis digiti III, medialis digiti IV). 

 The other division unites with the volar branch of the ulnar nerve to form the 

 lateral volar digital nerve of the lateral chief digit (N. digitalis lateralis digiti IV). 



The limibo-sacral plexus and its branches to the pelvis and thigh present no 

 very striking special features. 



The superficial peroneal nerve is much larger than in the horse. After crossing 

 beneath the peroneus longus it passes down on the front of the tarsus and meta- 

 tarsus and divides into three branches. The medial and lateral branches descend 

 as the medial and lateral dorsal digital nerves on the chief digits. The larger 

 middle branch joins a branch of the deep peroneal nerve in the interdigital space, 

 and from this union proceed the dorsal digital nerves which descend on the opposed 

 surfaces of the chief digits. 



The deep peroneal nerve descends in the leg as in the horse, and continues 

 down the dorsal groove of the metatarsus with the dorsal metatarsal artery. It 

 gives collateral branches to the anterior muscles of the leg and to the extensor 

 digitalis brevis. Its terminal branches concur with branches from the superficial 

 peroneal nerve in the formation of the two axial dorsal digital nerves (N. dig. dors, 

 lat. dig. Ill et dig. dors. med. dig. IV pedis), and with a branch of the medial 

 plantar nerve in the formation of corresponding plantar digital nerves. 



The tibial nerve divides at the back of the hock into medial and lateral plantar 

 nerves. The medial plantar nerve descends between the superficial flexor tendon 

 and the suspensory ligament and divides into two branches; the medial branch 

 descends as the medial plantar digital nerve (N. dig. plant, med. dig. Ill) along the 

 medial side of the flexor tendons of the medial chief digit; the lateral branch turns 

 around the flexor tendons to reach the interdigital space, where it concurs with a 

 branch of the deep peroneal nerve in the formation of two axial plantar digital 

 nerves (N. dig. plant, lat. dig. Ill et dig. plant, med. dig. IV), which descend on 

 the opposed surfaces of the chief digits. The lateral plantar nerve descends along 



